git.oblomov.eu Git - git/blob - unpack-trees.c

   1 #define NO_THE_INDEX_COMPATIBILITY_MACROS
   2 #include "cache.h"
   3 #include "dir.h"
   4 #include "tree.h"
   5 #include "tree-walk.h"
   6 #include "cache-tree.h"
   7 #include "unpack-trees.h"
   8 #include "progress.h"
   9 #include "refs.h"
  10 #include "attr.h"
  11 #include "split-index.h"
  12 #include "dir.h"
  13
  14 /*
  15  * Error messages expected by scripts out of plumbing commands such as
  16  * read-tree.  Non-scripted Porcelain is not required to use these messages
  17  * and in fact are encouraged to reword them to better suit their particular
  18  * situation better.  See how "git checkout" and "git merge" replaces
  19  * them using setup_unpack_trees_porcelain(), for example.
  20  */
  21 static const char *unpack_plumbing_errors[NB_UNPACK_TREES_ERROR_TYPES] = {
  22         /* ERROR_WOULD_OVERWRITE */
  23         "Entry '%s' would be overwritten by merge. Cannot merge.",
  24
  25         /* ERROR_NOT_UPTODATE_FILE */
  26         "Entry '%s' not uptodate. Cannot merge.",
  27
  28         /* ERROR_NOT_UPTODATE_DIR */
  29         "Updating '%s' would lose untracked files in it",
  30
  31         /* ERROR_WOULD_LOSE_UNTRACKED_OVERWRITTEN */
  32         "Untracked working tree file '%s' would be overwritten by merge.",
  33
  34         /* ERROR_WOULD_LOSE_UNTRACKED_REMOVED */
  35         "Untracked working tree file '%s' would be removed by merge.",
  36
  37         /* ERROR_BIND_OVERLAP */
  38         "Entry '%s' overlaps with '%s'.  Cannot bind.",
  39
  40         /* ERROR_SPARSE_NOT_UPTODATE_FILE */
  41         "Entry '%s' not uptodate. Cannot update sparse checkout.",
  42
  43         /* ERROR_WOULD_LOSE_ORPHANED_OVERWRITTEN */
  44         "Working tree file '%s' would be overwritten by sparse checkout update.",
  45
  46         /* ERROR_WOULD_LOSE_ORPHANED_REMOVED */
  47         "Working tree file '%s' would be removed by sparse checkout update.",
  48 };
  49
  50 #define ERRORMSG(o,type) \
  51         ( ((o) && (o)->msgs[(type)]) \
  52           ? ((o)->msgs[(type)])      \
  53           : (unpack_plumbing_errors[(type)]) )
  54
  55 static const char *super_prefixed(const char *path)
  56 {
  57         /*
  58          * It is necessary and sufficient to have two static buffers
  59          * here, as the return value of this function is fed to
  60          * error() using the unpack_*_errors[] templates we see above.
  61          */
  62         static struct strbuf buf[2] = {STRBUF_INIT, STRBUF_INIT};
  63         static int super_prefix_len = -1;
  64         static unsigned idx = ARRAY_SIZE(buf) - 1;
  65
  66         if (super_prefix_len < 0) {
  67                 const char *super_prefix = get_super_prefix();
  68                 if (!super_prefix) {
  69                         super_prefix_len = 0;
  70                 } else {
  71                         int i;
  72                         for (i = 0; i < ARRAY_SIZE(buf); i++)
  73                                 strbuf_addstr(&buf[i], super_prefix);
  74                         super_prefix_len = buf[0].len;
  75                 }
  76         }
  77
  78         if (!super_prefix_len)
  79                 return path;
  80
  81         if (++idx >= ARRAY_SIZE(buf))
  82                 idx = 0;
  83
  84         strbuf_setlen(&buf[idx], super_prefix_len);
  85         strbuf_addstr(&buf[idx], path);
  86
  87         return buf[idx].buf;
  88 }
  89
  90 void setup_unpack_trees_porcelain(struct unpack_trees_options *opts,
  91                                   const char *cmd)
  92 {
  93         int i;
  94         const char **msgs = opts->msgs;
  95         const char *msg;
  96
  97         if (!strcmp(cmd, "checkout"))
  98                 msg = advice_commit_before_merge
  99                       ? _("Your local changes to the following files would be overwritten by checkout:\n%%s"
 100                           "Please commit your changes or stash them before you switch branches.")
 101                       : _("Your local changes to the following files would be overwritten by checkout:\n%%s");
 102         else if (!strcmp(cmd, "merge"))
 103                 msg = advice_commit_before_merge
 104                       ? _("Your local changes to the following files would be overwritten by merge:\n%%s"
 105                           "Please commit your changes or stash them before you merge.")
 106                       : _("Your local changes to the following files would be overwritten by merge:\n%%s");
 107         else
 108                 msg = advice_commit_before_merge
 109                       ? _("Your local changes to the following files would be overwritten by %s:\n%%s"
 110                           "Please commit your changes or stash them before you %s.")
 111                       : _("Your local changes to the following files would be overwritten by %s:\n%%s");
 112         msgs[ERROR_WOULD_OVERWRITE] = msgs[ERROR_NOT_UPTODATE_FILE] =
 113                 xstrfmt(msg, cmd, cmd);
 114
 115         msgs[ERROR_NOT_UPTODATE_DIR] =
 116                 _("Updating the following directories would lose untracked files in them:\n%s");
 117
 118         if (!strcmp(cmd, "checkout"))
 119                 msg = advice_commit_before_merge
 120                       ? _("The following untracked working tree files would be removed by checkout:\n%%s"
 121                           "Please move or remove them before you switch branches.")
 122                       : _("The following untracked working tree files would be removed by checkout:\n%%s");
 123         else if (!strcmp(cmd, "merge"))
 124                 msg = advice_commit_before_merge
 125                       ? _("The following untracked working tree files would be removed by merge:\n%%s"
 126                           "Please move or remove them before you merge.")
 127                       : _("The following untracked working tree files would be removed by merge:\n%%s");
 128         else
 129                 msg = advice_commit_before_merge
 130                       ? _("The following untracked working tree files would be removed by %s:\n%%s"
 131                           "Please move or remove them before you %s.")
 132                       : _("The following untracked working tree files would be removed by %s:\n%%s");
 133         msgs[ERROR_WOULD_LOSE_UNTRACKED_REMOVED] = xstrfmt(msg, cmd, cmd);
 134
 135         if (!strcmp(cmd, "checkout"))
 136                 msg = advice_commit_before_merge
 137                       ? _("The following untracked working tree files would be overwritten by checkout:\n%%s"
 138                           "Please move or remove them before you switch branches.")
 139                       : _("The following untracked working tree files would be overwritten by checkout:\n%%s");
 140         else if (!strcmp(cmd, "merge"))
 141                 msg = advice_commit_before_merge
 142                       ? _("The following untracked working tree files would be overwritten by merge:\n%%s"
 143                           "Please move or remove them before you merge.")
 144                       : _("The following untracked working tree files would be overwritten by merge:\n%%s");
 145         else
 146                 msg = advice_commit_before_merge
 147                       ? _("The following untracked working tree files would be overwritten by %s:\n%%s"
 148                           "Please move or remove them before you %s.")
 149                       : _("The following untracked working tree files would be overwritten by %s:\n%%s");
 150         msgs[ERROR_WOULD_LOSE_UNTRACKED_OVERWRITTEN] = xstrfmt(msg, cmd, cmd);
 151
 152         /*
 153          * Special case: ERROR_BIND_OVERLAP refers to a pair of paths, we
 154          * cannot easily display it as a list.
 155          */
 156         msgs[ERROR_BIND_OVERLAP] = _("Entry '%s' overlaps with '%s'.  Cannot bind.");
 157
 158         msgs[ERROR_SPARSE_NOT_UPTODATE_FILE] =
 159                 _("Cannot update sparse checkout: the following entries are not up-to-date:\n%s");
 160         msgs[ERROR_WOULD_LOSE_ORPHANED_OVERWRITTEN] =
 161                 _("The following working tree files would be overwritten by sparse checkout update:\n%s");
 162         msgs[ERROR_WOULD_LOSE_ORPHANED_REMOVED] =
 163                 _("The following working tree files would be removed by sparse checkout update:\n%s");
 164
 165         opts->show_all_errors = 1;
 166         /* rejected paths may not have a static buffer */
 167         for (i = 0; i < ARRAY_SIZE(opts->unpack_rejects); i++)
 168                 opts->unpack_rejects[i].strdup_strings = 1;
 169 }
 170
 171 static int do_add_entry(struct unpack_trees_options *o, struct cache_entry *ce,
 172                          unsigned int set, unsigned int clear)
 173 {
 174         clear |= CE_HASHED;
 175
 176         if (set & CE_REMOVE)
 177                 set |= CE_WT_REMOVE;
 178
 179         ce->ce_flags = (ce->ce_flags & ~clear) | set;
 180         return add_index_entry(&o->result, ce,
 181                                ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE);
 182 }
 183
 184 static struct cache_entry *dup_entry(const struct cache_entry *ce)
 185 {
 186         unsigned int size = ce_size(ce);
 187         struct cache_entry *new = xmalloc(size);
 188
 189         memcpy(new, ce, size);
 190         return new;
 191 }
 192
 193 static void add_entry(struct unpack_trees_options *o,
 194                       const struct cache_entry *ce,
 195                       unsigned int set, unsigned int clear)
 196 {
 197         do_add_entry(o, dup_entry(ce), set, clear);
 198 }
 199
 200 /*
 201  * add error messages on path <path>
 202  * corresponding to the type <e> with the message <msg>
 203  * indicating if it should be display in porcelain or not
 204  */
 205 static int add_rejected_path(struct unpack_trees_options *o,
 206                              enum unpack_trees_error_types e,
 207                              const char *path)
 208 {
 209         if (!o->show_all_errors)
 210                 return error(ERRORMSG(o, e), super_prefixed(path));
 211
 212         /*
 213          * Otherwise, insert in a list for future display by
 214          * display_error_msgs()
 215          */
 216         string_list_append(&o->unpack_rejects[e], path);
 217         return -1;
 218 }
 219
 220 /*
 221  * display all the error messages stored in a nice way
 222  */
 223 static void display_error_msgs(struct unpack_trees_options *o)
 224 {
 225         int e, i;
 226         int something_displayed = 0;
 227         for (e = 0; e < NB_UNPACK_TREES_ERROR_TYPES; e++) {
 228                 struct string_list *rejects = &o->unpack_rejects[e];
 229                 if (rejects->nr > 0) {
 230                         struct strbuf path = STRBUF_INIT;
 231                         something_displayed = 1;
 232                         for (i = 0; i < rejects->nr; i++)
 233                                 strbuf_addf(&path, "\t%s\n", rejects->items[i].string);
 234                         error(ERRORMSG(o, e), super_prefixed(path.buf));
 235                         strbuf_release(&path);
 236                 }
 237                 string_list_clear(rejects, 0);
 238         }
 239         if (something_displayed)
 240                 fprintf(stderr, _("Aborting\n"));
 241 }
 242
 243 /*
 244  * Unlink the last component and schedule the leading directories for
 245  * removal, such that empty directories get removed.
 246  */
 247 static void unlink_entry(const struct cache_entry *ce)
 248 {
 249         if (!check_leading_path(ce->name, ce_namelen(ce)))
 250                 return;
 251         if (remove_or_warn(ce->ce_mode, ce->name))
 252                 return;
 253         schedule_dir_for_removal(ce->name, ce_namelen(ce));
 254 }
 255
 256 static struct progress *get_progress(struct unpack_trees_options *o)
 257 {
 258         unsigned cnt = 0, total = 0;
 259         struct index_state *index = &o->result;
 260
 261         if (!o->update || !o->verbose_update)
 262                 return NULL;
 263
 264         for (; cnt < index->cache_nr; cnt++) {
 265                 const struct cache_entry *ce = index->cache[cnt];
 266                 if (ce->ce_flags & (CE_UPDATE | CE_WT_REMOVE))
 267                         total++;
 268         }
 269
 270         return start_progress_delay(_("Checking out files"),
 271                                     total, 50, 1);
 272 }
 273
 274 static int check_updates(struct unpack_trees_options *o)
 275 {
 276         unsigned cnt = 0;
 277         int errs = 0;
 278         struct progress *progress = NULL;
 279         struct index_state *index = &o->result;
 280         struct checkout state = CHECKOUT_INIT;
 281         int i;
 282
 283         state.force = 1;
 284         state.quiet = 1;
 285         state.refresh_cache = 1;
 286         state.istate = index;
 287
 288         progress = get_progress(o);
 289
 290         if (o->update)
 291                 git_attr_set_direction(GIT_ATTR_CHECKOUT, index);
 292         for (i = 0; i < index->cache_nr; i++) {
 293                 const struct cache_entry *ce = index->cache[i];
 294
 295                 if (ce->ce_flags & CE_WT_REMOVE) {
 296                         display_progress(progress, ++cnt);
 297                         if (o->update && !o->dry_run)
 298                                 unlink_entry(ce);
 299                 }
 300         }
 301         remove_marked_cache_entries(index);
 302         remove_scheduled_dirs();
 303
 304         for (i = 0; i < index->cache_nr; i++) {
 305                 struct cache_entry *ce = index->cache[i];
 306
 307                 if (ce->ce_flags & CE_UPDATE) {
 308                         if (ce->ce_flags & CE_WT_REMOVE)
 309                                 die("BUG: both update and delete flags are set on %s",
 310                                     ce->name);
 311                         display_progress(progress, ++cnt);
 312                         ce->ce_flags &= ~CE_UPDATE;
 313                         if (o->update && !o->dry_run) {
 314                                 errs |= checkout_entry(ce, &state, NULL);
 315                         }
 316                 }
 317         }
 318         stop_progress(&progress);
 319         if (o->update)
 320                 git_attr_set_direction(GIT_ATTR_CHECKIN, NULL);
 321         return errs != 0;
 322 }
 323
 324 static int verify_uptodate_sparse(const struct cache_entry *ce,
 325                                   struct unpack_trees_options *o);
 326 static int verify_absent_sparse(const struct cache_entry *ce,
 327                                 enum unpack_trees_error_types,
 328                                 struct unpack_trees_options *o);
 329
 330 static int apply_sparse_checkout(struct index_state *istate,
 331                                  struct cache_entry *ce,
 332                                  struct unpack_trees_options *o)
 333 {
 334         int was_skip_worktree = ce_skip_worktree(ce);
 335
 336         if (ce->ce_flags & CE_NEW_SKIP_WORKTREE)
 337                 ce->ce_flags |= CE_SKIP_WORKTREE;
 338         else
 339                 ce->ce_flags &= ~CE_SKIP_WORKTREE;
 340         if (was_skip_worktree != ce_skip_worktree(ce)) {
 341                 ce->ce_flags |= CE_UPDATE_IN_BASE;
 342                 istate->cache_changed |= CE_ENTRY_CHANGED;
 343         }
 344
 345         /*
 346          * if (!was_skip_worktree && !ce_skip_worktree()) {
 347          *      This is perfectly normal. Move on;
 348          * }
 349          */
 350
 351         /*
 352          * Merge strategies may set CE_UPDATE|CE_REMOVE outside checkout
 353          * area as a result of ce_skip_worktree() shortcuts in
 354          * verify_absent() and verify_uptodate().
 355          * Make sure they don't modify worktree if they are already
 356          * outside checkout area
 357          */
 358         if (was_skip_worktree && ce_skip_worktree(ce)) {
 359                 ce->ce_flags &= ~CE_UPDATE;
 360
 361                 /*
 362                  * By default, when CE_REMOVE is on, CE_WT_REMOVE is also
 363                  * on to get that file removed from both index and worktree.
 364                  * If that file is already outside worktree area, don't
 365                  * bother remove it.
 366                  */
 367                 if (ce->ce_flags & CE_REMOVE)
 368                         ce->ce_flags &= ~CE_WT_REMOVE;
 369         }
 370
 371         if (!was_skip_worktree && ce_skip_worktree(ce)) {
 372                 /*
 373                  * If CE_UPDATE is set, verify_uptodate() must be called already
 374                  * also stat info may have lost after merged_entry() so calling
 375                  * verify_uptodate() again may fail
 376                  */
 377                 if (!(ce->ce_flags & CE_UPDATE) && verify_uptodate_sparse(ce, o))
 378                         return -1;
 379                 ce->ce_flags |= CE_WT_REMOVE;
 380                 ce->ce_flags &= ~CE_UPDATE;
 381         }
 382         if (was_skip_worktree && !ce_skip_worktree(ce)) {
 383                 if (verify_absent_sparse(ce, ERROR_WOULD_LOSE_UNTRACKED_OVERWRITTEN, o))
 384                         return -1;
 385                 ce->ce_flags |= CE_UPDATE;
 386         }
 387         return 0;
 388 }
 389
 390 static inline int call_unpack_fn(const struct cache_entry * const *src,
 391                                  struct unpack_trees_options *o)
 392 {
 393         int ret = o->fn(src, o);
 394         if (ret > 0)
 395                 ret = 0;
 396         return ret;
 397 }
 398
 399 static void mark_ce_used(struct cache_entry *ce, struct unpack_trees_options *o)
 400 {
 401         ce->ce_flags |= CE_UNPACKED;
 402
 403         if (o->cache_bottom < o->src_index->cache_nr &&
 404             o->src_index->cache[o->cache_bottom] == ce) {
 405                 int bottom = o->cache_bottom;
 406                 while (bottom < o->src_index->cache_nr &&
 407                        o->src_index->cache[bottom]->ce_flags & CE_UNPACKED)
 408                         bottom++;
 409                 o->cache_bottom = bottom;
 410         }
 411 }
 412
 413 static void mark_all_ce_unused(struct index_state *index)
 414 {
 415         int i;
 416         for (i = 0; i < index->cache_nr; i++)
 417                 index->cache[i]->ce_flags &= ~(CE_UNPACKED | CE_ADDED | CE_NEW_SKIP_WORKTREE);
 418 }
 419
 420 static int locate_in_src_index(const struct cache_entry *ce,
 421                                struct unpack_trees_options *o)
 422 {
 423         struct index_state *index = o->src_index;
 424         int len = ce_namelen(ce);
 425         int pos = index_name_pos(index, ce->name, len);
 426         if (pos < 0)
 427                 pos = -1 - pos;
 428         return pos;
 429 }
 430
 431 /*
 432  * We call unpack_index_entry() with an unmerged cache entry
 433  * only in diff-index, and it wants a single callback.  Skip
 434  * the other unmerged entry with the same name.
 435  */
 436 static void mark_ce_used_same_name(struct cache_entry *ce,
 437                                    struct unpack_trees_options *o)
 438 {
 439         struct index_state *index = o->src_index;
 440         int len = ce_namelen(ce);
 441         int pos;
 442
 443         for (pos = locate_in_src_index(ce, o); pos < index->cache_nr; pos++) {
 444                 struct cache_entry *next = index->cache[pos];
 445                 if (len != ce_namelen(next) ||
 446                     memcmp(ce->name, next->name, len))
 447                         break;
 448                 mark_ce_used(next, o);
 449         }
 450 }
 451
 452 static struct cache_entry *next_cache_entry(struct unpack_trees_options *o)
 453 {
 454         const struct index_state *index = o->src_index;
 455         int pos = o->cache_bottom;
 456
 457         while (pos < index->cache_nr) {
 458                 struct cache_entry *ce = index->cache[pos];
 459                 if (!(ce->ce_flags & CE_UNPACKED))
 460                         return ce;
 461                 pos++;
 462         }
 463         return NULL;
 464 }
 465
 466 static void add_same_unmerged(const struct cache_entry *ce,
 467                               struct unpack_trees_options *o)
 468 {
 469         struct index_state *index = o->src_index;
 470         int len = ce_namelen(ce);
 471         int pos = index_name_pos(index, ce->name, len);
 472
 473         if (0 <= pos)
 474                 die("programming error in a caller of mark_ce_used_same_name");
 475         for (pos = -pos - 1; pos < index->cache_nr; pos++) {
 476                 struct cache_entry *next = index->cache[pos];
 477                 if (len != ce_namelen(next) ||
 478                     memcmp(ce->name, next->name, len))
 479                         break;
 480                 add_entry(o, next, 0, 0);
 481                 mark_ce_used(next, o);
 482         }
 483 }
 484
 485 static int unpack_index_entry(struct cache_entry *ce,
 486                               struct unpack_trees_options *o)
 487 {
 488         const struct cache_entry *src[MAX_UNPACK_TREES + 1] = { NULL, };
 489         int ret;
 490
 491         src[0] = ce;
 492
 493         mark_ce_used(ce, o);
 494         if (ce_stage(ce)) {
 495                 if (o->skip_unmerged) {
 496                         add_entry(o, ce, 0, 0);
 497                         return 0;
 498                 }
 499         }
 500         ret = call_unpack_fn(src, o);
 501         if (ce_stage(ce))
 502                 mark_ce_used_same_name(ce, o);
 503         return ret;
 504 }
 505
 506 static int find_cache_pos(struct traverse_info *, const struct name_entry *);
 507
 508 static void restore_cache_bottom(struct traverse_info *info, int bottom)
 509 {
 510         struct unpack_trees_options *o = info->data;
 511
 512         if (o->diff_index_cached)
 513                 return;
 514         o->cache_bottom = bottom;
 515 }
 516
 517 static int switch_cache_bottom(struct traverse_info *info)
 518 {
 519         struct unpack_trees_options *o = info->data;
 520         int ret, pos;
 521
 522         if (o->diff_index_cached)
 523                 return 0;
 524         ret = o->cache_bottom;
 525         pos = find_cache_pos(info->prev, &info->name);
 526
 527         if (pos < -1)
 528                 o->cache_bottom = -2 - pos;
 529         else if (pos < 0)
 530                 o->cache_bottom = o->src_index->cache_nr;
 531         return ret;
 532 }
 533
 534 static int traverse_trees_recursive(int n, unsigned long dirmask,
 535                                     unsigned long df_conflicts,
 536                                     struct name_entry *names,
 537                                     struct traverse_info *info)
 538 {
 539         int i, ret, bottom;
 540         struct tree_desc t[MAX_UNPACK_TREES];
 541         void *buf[MAX_UNPACK_TREES];
 542         struct traverse_info newinfo;
 543         struct name_entry *p;
 544
 545         p = names;
 546         while (!p->mode)
 547                 p++;
 548
 549         newinfo = *info;
 550         newinfo.prev = info;
 551         newinfo.pathspec = info->pathspec;
 552         newinfo.name = *p;
 553         newinfo.pathlen += tree_entry_len(p) + 1;
 554         newinfo.df_conflicts |= df_conflicts;
 555
 556         for (i = 0; i < n; i++, dirmask >>= 1) {
 557                 const unsigned char *sha1 = NULL;
 558                 if (dirmask & 1)
 559                         sha1 = names[i].oid->hash;
 560                 buf[i] = fill_tree_descriptor(t+i, sha1);
 561         }
 562
 563         bottom = switch_cache_bottom(&newinfo);
 564         ret = traverse_trees(n, t, &newinfo);
 565         restore_cache_bottom(&newinfo, bottom);
 566
 567         for (i = 0; i < n; i++)
 568                 free(buf[i]);
 569
 570         return ret;
 571 }
 572
 573 /*
 574  * Compare the traverse-path to the cache entry without actually
 575  * having to generate the textual representation of the traverse
 576  * path.
 577  *
 578  * NOTE! This *only* compares up to the size of the traverse path
 579  * itself - the caller needs to do the final check for the cache
 580  * entry having more data at the end!
 581  */
 582 static int do_compare_entry_piecewise(const struct cache_entry *ce, const struct traverse_info *info, const struct name_entry *n)
 583 {
 584         int len, pathlen, ce_len;
 585         const char *ce_name;
 586
 587         if (info->prev) {
 588                 int cmp = do_compare_entry_piecewise(ce, info->prev,
 589                                                      &info->name);
 590                 if (cmp)
 591                         return cmp;
 592         }
 593         pathlen = info->pathlen;
 594         ce_len = ce_namelen(ce);
 595
 596         /* If ce_len < pathlen then we must have previously hit "name == directory" entry */
 597         if (ce_len < pathlen)
 598                 return -1;
 599
 600         ce_len -= pathlen;
 601         ce_name = ce->name + pathlen;
 602
 603         len = tree_entry_len(n);
 604         return df_name_compare(ce_name, ce_len, S_IFREG, n->path, len, n->mode);
 605 }
 606
 607 static int do_compare_entry(const struct cache_entry *ce,
 608                             const struct traverse_info *info,
 609                             const struct name_entry *n)
 610 {
 611         int len, pathlen, ce_len;
 612         const char *ce_name;
 613         int cmp;
 614
 615         /*
 616          * If we have not precomputed the traverse path, it is quicker
 617          * to avoid doing so.  But if we have precomputed it,
 618          * it is quicker to use the precomputed version.
 619          */
 620         if (!info->traverse_path)
 621                 return do_compare_entry_piecewise(ce, info, n);
 622
 623         cmp = strncmp(ce->name, info->traverse_path, info->pathlen);
 624         if (cmp)
 625                 return cmp;
 626
 627         pathlen = info->pathlen;
 628         ce_len = ce_namelen(ce);
 629
 630         if (ce_len < pathlen)
 631                 return -1;
 632
 633         ce_len -= pathlen;
 634         ce_name = ce->name + pathlen;
 635
 636         len = tree_entry_len(n);
 637         return df_name_compare(ce_name, ce_len, S_IFREG, n->path, len, n->mode);
 638 }
 639
 640 static int compare_entry(const struct cache_entry *ce, const struct traverse_info *info, const struct name_entry *n)
 641 {
 642         int cmp = do_compare_entry(ce, info, n);
 643         if (cmp)
 644                 return cmp;
 645
 646         /*
 647          * Even if the beginning compared identically, the ce should
 648          * compare as bigger than a directory leading up to it!
 649          */
 650         return ce_namelen(ce) > traverse_path_len(info, n);
 651 }
 652
 653 static int ce_in_traverse_path(const struct cache_entry *ce,
 654                                const struct traverse_info *info)
 655 {
 656         if (!info->prev)
 657                 return 1;
 658         if (do_compare_entry(ce, info->prev, &info->name))
 659                 return 0;
 660         /*
 661          * If ce (blob) is the same name as the path (which is a tree
 662          * we will be descending into), it won't be inside it.
 663          */
 664         return (info->pathlen < ce_namelen(ce));
 665 }
 666
 667 static struct cache_entry *create_ce_entry(const struct traverse_info *info, const struct name_entry *n, int stage)
 668 {
 669         int len = traverse_path_len(info, n);
 670         struct cache_entry *ce = xcalloc(1, cache_entry_size(len));
 671
 672         ce->ce_mode = create_ce_mode(n->mode);
 673         ce->ce_flags = create_ce_flags(stage);
 674         ce->ce_namelen = len;
 675         oidcpy(&ce->oid, n->oid);
 676         make_traverse_path(ce->name, info, n);
 677
 678         return ce;
 679 }
 680
 681 static int unpack_nondirectories(int n, unsigned long mask,
 682                                  unsigned long dirmask,
 683                                  struct cache_entry **src,
 684                                  const struct name_entry *names,
 685                                  const struct traverse_info *info)
 686 {
 687         int i;
 688         struct unpack_trees_options *o = info->data;
 689         unsigned long conflicts = info->df_conflicts | dirmask;
 690
 691         /* Do we have *only* directories? Nothing to do */
 692         if (mask == dirmask && !src[0])
 693                 return 0;
 694
 695         /*
 696          * Ok, we've filled in up to any potential index entry in src[0],
 697          * now do the rest.
 698          */
 699         for (i = 0; i < n; i++) {
 700                 int stage;
 701                 unsigned int bit = 1ul << i;
 702                 if (conflicts & bit) {
 703                         src[i + o->merge] = o->df_conflict_entry;
 704                         continue;
 705                 }
 706                 if (!(mask & bit))
 707                         continue;
 708                 if (!o->merge)
 709                         stage = 0;
 710                 else if (i + 1 < o->head_idx)
 711                         stage = 1;
 712                 else if (i + 1 > o->head_idx)
 713                         stage = 3;
 714                 else
 715                         stage = 2;
 716                 src[i + o->merge] = create_ce_entry(info, names + i, stage);
 717         }
 718
 719         if (o->merge) {
 720                 int rc = call_unpack_fn((const struct cache_entry * const *)src,
 721                                         o);
 722                 for (i = 0; i < n; i++) {
 723                         struct cache_entry *ce = src[i + o->merge];
 724                         if (ce != o->df_conflict_entry)
 725                                 free(ce);
 726                 }
 727                 return rc;
 728         }
 729
 730         for (i = 0; i < n; i++)
 731                 if (src[i] && src[i] != o->df_conflict_entry)
 732                         if (do_add_entry(o, src[i], 0, 0))
 733                                 return -1;
 734
 735         return 0;
 736 }
 737
 738 static int unpack_failed(struct unpack_trees_options *o, const char *message)
 739 {
 740         discard_index(&o->result);
 741         if (!o->gently && !o->exiting_early) {
 742                 if (message)
 743                         return error("%s", message);
 744                 return -1;
 745         }
 746         return -1;
 747 }
 748
 749 /*
 750  * The tree traversal is looking at name p.  If we have a matching entry,
 751  * return it.  If name p is a directory in the index, do not return
 752  * anything, as we will want to match it when the traversal descends into
 753  * the directory.
 754  */
 755 static int find_cache_pos(struct traverse_info *info,
 756                           const struct name_entry *p)
 757 {
 758         int pos;
 759         struct unpack_trees_options *o = info->data;
 760         struct index_state *index = o->src_index;
 761         int pfxlen = info->pathlen;
 762         int p_len = tree_entry_len(p);
 763
 764         for (pos = o->cache_bottom; pos < index->cache_nr; pos++) {
 765                 const struct cache_entry *ce = index->cache[pos];
 766                 const char *ce_name, *ce_slash;
 767                 int cmp, ce_len;
 768
 769                 if (ce->ce_flags & CE_UNPACKED) {
 770                         /*
 771                          * cache_bottom entry is already unpacked, so
 772                          * we can never match it; don't check it
 773                          * again.
 774                          */
 775                         if (pos == o->cache_bottom)
 776                                 ++o->cache_bottom;
 777                         continue;
 778                 }
 779                 if (!ce_in_traverse_path(ce, info)) {
 780                         /*
 781                          * Check if we can skip future cache checks
 782                          * (because we're already past all possible
 783                          * entries in the traverse path).
 784                          */
 785                         if (info->traverse_path) {
 786                                 if (strncmp(ce->name, info->traverse_path,
 787                                             info->pathlen) > 0)
 788                                         break;
 789                         }
 790                         continue;
 791                 }
 792                 ce_name = ce->name + pfxlen;
 793                 ce_slash = strchr(ce_name, '/');
 794                 if (ce_slash)
 795                         ce_len = ce_slash - ce_name;
 796                 else
 797                         ce_len = ce_namelen(ce) - pfxlen;
 798                 cmp = name_compare(p->path, p_len, ce_name, ce_len);
 799                 /*
 800                  * Exact match; if we have a directory we need to
 801                  * delay returning it.
 802                  */
 803                 if (!cmp)
 804                         return ce_slash ? -2 - pos : pos;
 805                 if (0 < cmp)
 806                         continue; /* keep looking */
 807                 /*
 808                  * ce_name sorts after p->path; could it be that we
 809                  * have files under p->path directory in the index?
 810                  * E.g.  ce_name == "t-i", and p->path == "t"; we may
 811                  * have "t/a" in the index.
 812                  */
 813                 if (p_len < ce_len && !memcmp(ce_name, p->path, p_len) &&
 814                     ce_name[p_len] < '/')
 815                         continue; /* keep looking */
 816                 break;
 817         }
 818         return -1;
 819 }
 820
 821 static struct cache_entry *find_cache_entry(struct traverse_info *info,
 822                                             const struct name_entry *p)
 823 {
 824         int pos = find_cache_pos(info, p);
 825         struct unpack_trees_options *o = info->data;
 826
 827         if (0 <= pos)
 828                 return o->src_index->cache[pos];
 829         else
 830                 return NULL;
 831 }
 832
 833 static void debug_path(struct traverse_info *info)
 834 {
 835         if (info->prev) {
 836                 debug_path(info->prev);
 837                 if (*info->prev->name.path)
 838                         putchar('/');
 839         }
 840         printf("%s", info->name.path);
 841 }
 842
 843 static void debug_name_entry(int i, struct name_entry *n)
 844 {
 845         printf("ent#%d %06o %s\n", i,
 846                n->path ? n->mode : 0,
 847                n->path ? n->path : "(missing)");
 848 }
 849
 850 static void debug_unpack_callback(int n,
 851                                   unsigned long mask,
 852                                   unsigned long dirmask,
 853                                   struct name_entry *names,
 854                                   struct traverse_info *info)
 855 {
 856         int i;
 857         printf("* unpack mask %lu, dirmask %lu, cnt %d ",
 858                mask, dirmask, n);
 859         debug_path(info);
 860         putchar('\n');
 861         for (i = 0; i < n; i++)
 862                 debug_name_entry(i, names + i);
 863 }
 864
 865 static int unpack_callback(int n, unsigned long mask, unsigned long dirmask, struct name_entry *names, struct traverse_info *info)
 866 {
 867         struct cache_entry *src[MAX_UNPACK_TREES + 1] = { NULL, };
 868         struct unpack_trees_options *o = info->data;
 869         const struct name_entry *p = names;
 870
 871         /* Find first entry with a real name (we could use "mask" too) */
 872         while (!p->mode)
 873                 p++;
 874
 875         if (o->debug_unpack)
 876                 debug_unpack_callback(n, mask, dirmask, names, info);
 877
 878         /* Are we supposed to look at the index too? */
 879         if (o->merge) {
 880                 while (1) {
 881                         int cmp;
 882                         struct cache_entry *ce;
 883
 884                         if (o->diff_index_cached)
 885                                 ce = next_cache_entry(o);
 886                         else
 887                                 ce = find_cache_entry(info, p);
 888
 889                         if (!ce)
 890                                 break;
 891                         cmp = compare_entry(ce, info, p);
 892                         if (cmp < 0) {
 893                                 if (unpack_index_entry(ce, o) < 0)
 894                                         return unpack_failed(o, NULL);
 895                                 continue;
 896                         }
 897                         if (!cmp) {
 898                                 if (ce_stage(ce)) {
 899                                         /*
 900                                          * If we skip unmerged index
 901                                          * entries, we'll skip this
 902                                          * entry *and* the tree
 903                                          * entries associated with it!
 904                                          */
 905                                         if (o->skip_unmerged) {
 906                                                 add_same_unmerged(ce, o);
 907                                                 return mask;
 908                                         }
 909                                 }
 910                                 src[0] = ce;
 911                         }
 912                         break;
 913                 }
 914         }
 915
 916         if (unpack_nondirectories(n, mask, dirmask, src, names, info) < 0)
 917                 return -1;
 918
 919         if (o->merge && src[0]) {
 920                 if (ce_stage(src[0]))
 921                         mark_ce_used_same_name(src[0], o);
 922                 else
 923                         mark_ce_used(src[0], o);
 924         }
 925
 926         /* Now handle any directories.. */
 927         if (dirmask) {
 928                 /* special case: "diff-index --cached" looking at a tree */
 929                 if (o->diff_index_cached &&
 930                     n == 1 && dirmask == 1 && S_ISDIR(names->mode)) {
 931                         int matches;
 932                         matches = cache_tree_matches_traversal(o->src_index->cache_tree,
 933                                                                names, info);
 934                         /*
 935                          * Everything under the name matches; skip the
 936                          * entire hierarchy.  diff_index_cached codepath
 937                          * special cases D/F conflicts in such a way that
 938                          * it does not do any look-ahead, so this is safe.
 939                          */
 940                         if (matches) {
 941                                 o->cache_bottom += matches;
 942                                 return mask;
 943                         }
 944                 }
 945
 946                 if (traverse_trees_recursive(n, dirmask, mask & ~dirmask,
 947                                              names, info) < 0)
 948                         return -1;
 949                 return mask;
 950         }
 951
 952         return mask;
 953 }
 954
 955 static int clear_ce_flags_1(struct cache_entry **cache, int nr,
 956                             struct strbuf *prefix,
 957                             int select_mask, int clear_mask,
 958                             struct exclude_list *el, int defval);
 959
 960 /* Whole directory matching */
 961 static int clear_ce_flags_dir(struct cache_entry **cache, int nr,
 962                               struct strbuf *prefix,
 963                               char *basename,
 964                               int select_mask, int clear_mask,
 965                               struct exclude_list *el, int defval)
 966 {
 967         struct cache_entry **cache_end;
 968         int dtype = DT_DIR;
 969         int ret = is_excluded_from_list(prefix->buf, prefix->len,
 970                                         basename, &dtype, el);
 971         int rc;
 972
 973         strbuf_addch(prefix, '/');
 974
 975         /* If undecided, use matching result of parent dir in defval */
 976         if (ret < 0)
 977                 ret = defval;
 978
 979         for (cache_end = cache; cache_end != cache + nr; cache_end++) {
 980                 struct cache_entry *ce = *cache_end;
 981                 if (strncmp(ce->name, prefix->buf, prefix->len))
 982                         break;
 983         }
 984
 985         /*
 986          * TODO: check el, if there are no patterns that may conflict
 987          * with ret (iow, we know in advance the incl/excl
 988          * decision for the entire directory), clear flag here without
 989          * calling clear_ce_flags_1(). That function will call
 990          * the expensive is_excluded_from_list() on every entry.
 991          */
 992         rc = clear_ce_flags_1(cache, cache_end - cache,
 993                               prefix,
 994                               select_mask, clear_mask,
 995                               el, ret);
 996         strbuf_setlen(prefix, prefix->len - 1);
 997         return rc;
 998 }
 999
1000 /*
1001  * Traverse the index, find every entry that matches according to
1002  * o->el. Do "ce_flags &= ~clear_mask" on those entries. Return the
1003  * number of traversed entries.
1004  *
1005  * If select_mask is non-zero, only entries whose ce_flags has on of
1006  * those bits enabled are traversed.
1007  *
1008  * cache        : pointer to an index entry
1009  * prefix_len   : an offset to its path
1010  *
1011  * The current path ("prefix") including the trailing '/' is
1012  *   cache[0]->name[0..(prefix_len-1)]
1013  * Top level path has prefix_len zero.
1014  */
1015 static int clear_ce_flags_1(struct cache_entry **cache, int nr,
1016                             struct strbuf *prefix,
1017                             int select_mask, int clear_mask,
1018                             struct exclude_list *el, int defval)
1019 {
1020         struct cache_entry **cache_end = cache + nr;
1021
1022         /*
1023          * Process all entries that have the given prefix and meet
1024          * select_mask condition
1025          */
1026         while(cache != cache_end) {
1027                 struct cache_entry *ce = *cache;
1028                 const char *name, *slash;
1029                 int len, dtype, ret;
1030
1031                 if (select_mask && !(ce->ce_flags & select_mask)) {
1032                         cache++;
1033                         continue;
1034                 }
1035
1036                 if (prefix->len && strncmp(ce->name, prefix->buf, prefix->len))
1037                         break;
1038
1039                 name = ce->name + prefix->len;
1040                 slash = strchr(name, '/');
1041
1042                 /* If it's a directory, try whole directory match first */
1043                 if (slash) {
1044                         int processed;
1045
1046                         len = slash - name;
1047                         strbuf_add(prefix, name, len);
1048
1049                         processed = clear_ce_flags_dir(cache, cache_end - cache,
1050                                                        prefix,
1051                                                        prefix->buf + prefix->len - len,
1052                                                        select_mask, clear_mask,
1053                                                        el, defval);
1054
1055                         /* clear_c_f_dir eats a whole dir already? */
1056                         if (processed) {
1057                                 cache += processed;
1058                                 strbuf_setlen(prefix, prefix->len - len);
1059                                 continue;
1060                         }
1061
1062                         strbuf_addch(prefix, '/');
1063                         cache += clear_ce_flags_1(cache, cache_end - cache,
1064                                                   prefix,
1065                                                   select_mask, clear_mask, el, defval);
1066                         strbuf_setlen(prefix, prefix->len - len - 1);
1067                         continue;
1068                 }
1069
1070                 /* Non-directory */
1071                 dtype = ce_to_dtype(ce);
1072                 ret = is_excluded_from_list(ce->name, ce_namelen(ce),
1073                                             name, &dtype, el);
1074                 if (ret < 0)
1075                         ret = defval;
1076                 if (ret > 0)
1077                         ce->ce_flags &= ~clear_mask;
1078                 cache++;
1079         }
1080         return nr - (cache_end - cache);
1081 }
1082
1083 static int clear_ce_flags(struct cache_entry **cache, int nr,
1084                             int select_mask, int clear_mask,
1085                             struct exclude_list *el)
1086 {
1087         static struct strbuf prefix = STRBUF_INIT;
1088
1089         strbuf_reset(&prefix);
1090
1091         return clear_ce_flags_1(cache, nr,
1092                                 &prefix,
1093                                 select_mask, clear_mask,
1094                                 el, 0);
1095 }
1096
1097 /*
1098  * Set/Clear CE_NEW_SKIP_WORKTREE according to $GIT_DIR/info/sparse-checkout
1099  */
1100 static void mark_new_skip_worktree(struct exclude_list *el,
1101                                    struct index_state *the_index,
1102                                    int select_flag, int skip_wt_flag)
1103 {
1104         int i;
1105
1106         /*
1107          * 1. Pretend the narrowest worktree: only unmerged entries
1108          * are checked out
1109          */
1110         for (i = 0; i < the_index->cache_nr; i++) {
1111                 struct cache_entry *ce = the_index->cache[i];
1112
1113                 if (select_flag && !(ce->ce_flags & select_flag))
1114                         continue;
1115
1116                 if (!ce_stage(ce))
1117                         ce->ce_flags |= skip_wt_flag;
1118                 else
1119                         ce->ce_flags &= ~skip_wt_flag;
1120         }
1121
1122         /*
1123          * 2. Widen worktree according to sparse-checkout file.
1124          * Matched entries will have skip_wt_flag cleared (i.e. "in")
1125          */
1126         clear_ce_flags(the_index->cache, the_index->cache_nr,
1127                        select_flag, skip_wt_flag, el);
1128 }
1129
1130 static int verify_absent(const struct cache_entry *,
1131                          enum unpack_trees_error_types,
1132                          struct unpack_trees_options *);
1133 /*
1134  * N-way merge "len" trees.  Returns 0 on success, -1 on failure to manipulate the
1135  * resulting index, -2 on failure to reflect the changes to the work tree.
1136  *
1137  * CE_ADDED, CE_UNPACKED and CE_NEW_SKIP_WORKTREE are used internally
1138  */
1139 int unpack_trees(unsigned len, struct tree_desc *t, struct unpack_trees_options *o)
1140 {
1141         int i, ret;
1142         static struct cache_entry *dfc;
1143         struct exclude_list el;
1144
1145         if (len > MAX_UNPACK_TREES)
1146                 die("unpack_trees takes at most %d trees", MAX_UNPACK_TREES);
1147
1148         memset(&el, 0, sizeof(el));
1149         if (!core_apply_sparse_checkout || !o->update)
1150                 o->skip_sparse_checkout = 1;
1151         if (!o->skip_sparse_checkout) {
1152                 char *sparse = git_pathdup("info/sparse-checkout");
1153                 if (add_excludes_from_file_to_list(sparse, "", 0, &el, 0) < 0)
1154                         o->skip_sparse_checkout = 1;
1155                 else
1156                         o->el = &el;
1157                 free(sparse);
1158         }
1159
1160         memset(&o->result, 0, sizeof(o->result));
1161         o->result.initialized = 1;
1162         o->result.timestamp.sec = o->src_index->timestamp.sec;
1163         o->result.timestamp.nsec = o->src_index->timestamp.nsec;
1164         o->result.version = o->src_index->version;
1165         o->result.split_index = o->src_index->split_index;
1166         if (o->result.split_index)
1167                 o->result.split_index->refcount++;
1168         hashcpy(o->result.sha1, o->src_index->sha1);
1169         o->merge_size = len;
1170         mark_all_ce_unused(o->src_index);
1171
1172         /*
1173          * Sparse checkout loop #1: set NEW_SKIP_WORKTREE on existing entries
1174          */
1175         if (!o->skip_sparse_checkout)
1176                 mark_new_skip_worktree(o->el, o->src_index, 0, CE_NEW_SKIP_WORKTREE);
1177
1178         if (!dfc)
1179                 dfc = xcalloc(1, cache_entry_size(0));
1180         o->df_conflict_entry = dfc;
1181
1182         if (len) {
1183                 const char *prefix = o->prefix ? o->prefix : "";
1184                 struct traverse_info info;
1185
1186                 setup_traverse_info(&info, prefix);
1187                 info.fn = unpack_callback;
1188                 info.data = o;
1189                 info.show_all_errors = o->show_all_errors;
1190                 info.pathspec = o->pathspec;
1191
1192                 if (o->prefix) {
1193                         /*
1194                          * Unpack existing index entries that sort before the
1195                          * prefix the tree is spliced into.  Note that o->merge
1196                          * is always true in this case.
1197                          */
1198                         while (1) {
1199                                 struct cache_entry *ce = next_cache_entry(o);
1200                                 if (!ce)
1201                                         break;
1202                                 if (ce_in_traverse_path(ce, &info))
1203                                         break;
1204                                 if (unpack_index_entry(ce, o) < 0)
1205                                         goto return_failed;
1206                         }
1207                 }
1208
1209                 if (traverse_trees(len, t, &info) < 0)
1210                         goto return_failed;
1211         }
1212
1213         /* Any left-over entries in the index? */
1214         if (o->merge) {
1215                 while (1) {
1216                         struct cache_entry *ce = next_cache_entry(o);
1217                         if (!ce)
1218                                 break;
1219                         if (unpack_index_entry(ce, o) < 0)
1220                                 goto return_failed;
1221                 }
1222         }
1223         mark_all_ce_unused(o->src_index);
1224
1225         if (o->trivial_merges_only && o->nontrivial_merge) {
1226                 ret = unpack_failed(o, "Merge requires file-level merging");
1227                 goto done;
1228         }
1229
1230         if (!o->skip_sparse_checkout) {
1231                 int empty_worktree = 1;
1232
1233                 /*
1234                  * Sparse checkout loop #2: set NEW_SKIP_WORKTREE on entries not in loop #1
1235                  * If the will have NEW_SKIP_WORKTREE, also set CE_SKIP_WORKTREE
1236                  * so apply_sparse_checkout() won't attempt to remove it from worktree
1237                  */
1238                 mark_new_skip_worktree(o->el, &o->result, CE_ADDED, CE_SKIP_WORKTREE | CE_NEW_SKIP_WORKTREE);
1239
1240                 ret = 0;
1241                 for (i = 0; i < o->result.cache_nr; i++) {
1242                         struct cache_entry *ce = o->result.cache[i];
1243
1244                         /*
1245                          * Entries marked with CE_ADDED in merged_entry() do not have
1246                          * verify_absent() check (the check is effectively disabled
1247                          * because CE_NEW_SKIP_WORKTREE is set unconditionally).
1248                          *
1249                          * Do the real check now because we have had
1250                          * correct CE_NEW_SKIP_WORKTREE
1251                          */
1252                         if (ce->ce_flags & CE_ADDED &&
1253                             verify_absent(ce, ERROR_WOULD_LOSE_UNTRACKED_OVERWRITTEN, o)) {
1254                                 if (!o->show_all_errors)
1255                                         goto return_failed;
1256                                 ret = -1;
1257                         }
1258
1259                         if (apply_sparse_checkout(&o->result, ce, o)) {
1260                                 if (!o->show_all_errors)
1261                                         goto return_failed;
1262                                 ret = -1;
1263                         }
1264                         if (!ce_skip_worktree(ce))
1265                                 empty_worktree = 0;
1266
1267                 }
1268                 if (ret < 0)
1269                         goto return_failed;
1270                 /*
1271                  * Sparse checkout is meant to narrow down checkout area
1272                  * but it does not make sense to narrow down to empty working
1273                  * tree. This is usually a mistake in sparse checkout rules.
1274                  * Do not allow users to do that.
1275                  */
1276                 if (o->result.cache_nr && empty_worktree) {
1277                         ret = unpack_failed(o, "Sparse checkout leaves no entry on working directory");
1278                         goto done;
1279                 }
1280         }
1281
1282         o->src_index = NULL;
1283         ret = check_updates(o) ? (-2) : 0;
1284         if (o->dst_index) {
1285                 if (!ret) {
1286                         if (!o->result.cache_tree)
1287                                 o->result.cache_tree = cache_tree();
1288                         if (!cache_tree_fully_valid(o->result.cache_tree))
1289                                 cache_tree_update(&o->result,
1290                                                   WRITE_TREE_SILENT |
1291                                                   WRITE_TREE_REPAIR);
1292                 }
1293                 discard_index(o->dst_index);
1294                 *o->dst_index = o->result;
1295         } else {
1296                 discard_index(&o->result);
1297         }
1298
1299 done:
1300         clear_exclude_list(&el);
1301         return ret;
1302
1303 return_failed:
1304         if (o->show_all_errors)
1305                 display_error_msgs(o);
1306         mark_all_ce_unused(o->src_index);
1307         ret = unpack_failed(o, NULL);
1308         if (o->exiting_early)
1309                 ret = 0;
1310         goto done;
1311 }
1312
1313 /* Here come the merge functions */
1314
1315 static int reject_merge(const struct cache_entry *ce,
1316                         struct unpack_trees_options *o)
1317 {
1318         return o->gently ? -1 :
1319                 add_rejected_path(o, ERROR_WOULD_OVERWRITE, ce->name);
1320 }
1321
1322 static int same(const struct cache_entry *a, const struct cache_entry *b)
1323 {
1324         if (!!a != !!b)
1325                 return 0;
1326         if (!a && !b)
1327                 return 1;
1328         if ((a->ce_flags | b->ce_flags) & CE_CONFLICTED)
1329                 return 0;
1330         return a->ce_mode == b->ce_mode &&
1331                !oidcmp(&a->oid, &b->oid);
1332 }
1333
1334
1335 /*
1336  * When a CE gets turned into an unmerged entry, we
1337  * want it to be up-to-date
1338  */
1339 static int verify_uptodate_1(const struct cache_entry *ce,
1340                              struct unpack_trees_options *o,
1341                              enum unpack_trees_error_types error_type)
1342 {
1343         struct stat st;
1344
1345         if (o->index_only)
1346                 return 0;
1347
1348         /*
1349          * CE_VALID and CE_SKIP_WORKTREE cheat, we better check again
1350          * if this entry is truly up-to-date because this file may be
1351          * overwritten.
1352          */
1353         if ((ce->ce_flags & CE_VALID) || ce_skip_worktree(ce))
1354                 ; /* keep checking */
1355         else if (o->reset || ce_uptodate(ce))
1356                 return 0;
1357
1358         if (!lstat(ce->name, &st)) {
1359                 int flags = CE_MATCH_IGNORE_VALID|CE_MATCH_IGNORE_SKIP_WORKTREE;
1360                 unsigned changed = ie_match_stat(o->src_index, ce, &st, flags);
1361                 if (!changed)
1362                         return 0;
1363                 /*
1364                  * NEEDSWORK: the current default policy is to allow
1365                  * submodule to be out of sync wrt the superproject
1366                  * index.  This needs to be tightened later for
1367                  * submodules that are marked to be automatically
1368                  * checked out.
1369                  */
1370                 if (S_ISGITLINK(ce->ce_mode))
1371                         return 0;
1372                 errno = 0;
1373         }
1374         if (errno == ENOENT)
1375                 return 0;
1376         return o->gently ? -1 :
1377                 add_rejected_path(o, error_type, ce->name);
1378 }
1379
1380 static int verify_uptodate(const struct cache_entry *ce,
1381                            struct unpack_trees_options *o)
1382 {
1383         if (!o->skip_sparse_checkout && (ce->ce_flags & CE_NEW_SKIP_WORKTREE))
1384                 return 0;
1385         return verify_uptodate_1(ce, o, ERROR_NOT_UPTODATE_FILE);
1386 }
1387
1388 static int verify_uptodate_sparse(const struct cache_entry *ce,
1389                                   struct unpack_trees_options *o)
1390 {
1391         return verify_uptodate_1(ce, o, ERROR_SPARSE_NOT_UPTODATE_FILE);
1392 }
1393
1394 static void invalidate_ce_path(const struct cache_entry *ce,
1395                                struct unpack_trees_options *o)
1396 {
1397         if (!ce)
1398                 return;
1399         cache_tree_invalidate_path(o->src_index, ce->name);
1400         untracked_cache_invalidate_path(o->src_index, ce->name);
1401 }
1402
1403 /*
1404  * Check that checking out ce->sha1 in subdir ce->name is not
1405  * going to overwrite any working files.
1406  *
1407  * Currently, git does not checkout subprojects during a superproject
1408  * checkout, so it is not going to overwrite anything.
1409  */
1410 static int verify_clean_submodule(const struct cache_entry *ce,
1411                                   enum unpack_trees_error_types error_type,
1412                                   struct unpack_trees_options *o)
1413 {
1414         return 0;
1415 }
1416
1417 static int verify_clean_subdirectory(const struct cache_entry *ce,
1418                                      enum unpack_trees_error_types error_type,
1419                                      struct unpack_trees_options *o)
1420 {
1421         /*
1422          * we are about to extract "ce->name"; we would not want to lose
1423          * anything in the existing directory there.
1424          */
1425         int namelen;
1426         int i;
1427         struct dir_struct d;
1428         char *pathbuf;
1429         int cnt = 0;
1430         unsigned char sha1[20];
1431
1432         if (S_ISGITLINK(ce->ce_mode) &&
1433             resolve_gitlink_ref(ce->name, "HEAD", sha1) == 0) {
1434                 /* If we are not going to update the submodule, then
1435                  * we don't care.
1436                  */
1437                 if (!hashcmp(sha1, ce->oid.hash))
1438                         return 0;
1439                 return verify_clean_submodule(ce, error_type, o);
1440         }
1441
1442         /*
1443          * First let's make sure we do not have a local modification
1444          * in that directory.
1445          */
1446         namelen = ce_namelen(ce);
1447         for (i = locate_in_src_index(ce, o);
1448              i < o->src_index->cache_nr;
1449              i++) {
1450                 struct cache_entry *ce2 = o->src_index->cache[i];
1451                 int len = ce_namelen(ce2);
1452                 if (len < namelen ||
1453                     strncmp(ce->name, ce2->name, namelen) ||
1454                     ce2->name[namelen] != '/')
1455                         break;
1456                 /*
1457                  * ce2->name is an entry in the subdirectory to be
1458                  * removed.
1459                  */
1460                 if (!ce_stage(ce2)) {
1461                         if (verify_uptodate(ce2, o))
1462                                 return -1;
1463                         add_entry(o, ce2, CE_REMOVE, 0);
1464                         mark_ce_used(ce2, o);
1465                 }
1466                 cnt++;
1467         }
1468
1469         /*
1470          * Then we need to make sure that we do not lose a locally
1471          * present file that is not ignored.
1472          */
1473         pathbuf = xstrfmt("%.*s/", namelen, ce->name);
1474
1475         memset(&d, 0, sizeof(d));
1476         if (o->dir)
1477                 d.exclude_per_dir = o->dir->exclude_per_dir;
1478         i = read_directory(&d, pathbuf, namelen+1, NULL);
1479         if (i)
1480                 return o->gently ? -1 :
1481                         add_rejected_path(o, ERROR_NOT_UPTODATE_DIR, ce->name);
1482         free(pathbuf);
1483         return cnt;
1484 }
1485
1486 /*
1487  * This gets called when there was no index entry for the tree entry 'dst',
1488  * but we found a file in the working tree that 'lstat()' said was fine,
1489  * and we're on a case-insensitive filesystem.
1490  *
1491  * See if we can find a case-insensitive match in the index that also
1492  * matches the stat information, and assume it's that other file!
1493  */
1494 static int icase_exists(struct unpack_trees_options *o, const char *name, int len, struct stat *st)
1495 {
1496         const struct cache_entry *src;
1497
1498         src = index_file_exists(o->src_index, name, len, 1);
1499         return src && !ie_match_stat(o->src_index, src, st, CE_MATCH_IGNORE_VALID|CE_MATCH_IGNORE_SKIP_WORKTREE);
1500 }
1501
1502 static int check_ok_to_remove(const char *name, int len, int dtype,
1503                               const struct cache_entry *ce, struct stat *st,
1504                               enum unpack_trees_error_types error_type,
1505                               struct unpack_trees_options *o)
1506 {
1507         const struct cache_entry *result;
1508
1509         /*
1510          * It may be that the 'lstat()' succeeded even though
1511          * target 'ce' was absent, because there is an old
1512          * entry that is different only in case..
1513          *
1514          * Ignore that lstat() if it matches.
1515          */
1516         if (ignore_case && icase_exists(o, name, len, st))
1517                 return 0;
1518
1519         if (o->dir &&
1520             is_excluded(o->dir, name, &dtype))
1521                 /*
1522                  * ce->name is explicitly excluded, so it is Ok to
1523                  * overwrite it.
1524                  */
1525                 return 0;
1526         if (S_ISDIR(st->st_mode)) {
1527                 /*
1528                  * We are checking out path "foo" and
1529                  * found "foo/." in the working tree.
1530                  * This is tricky -- if we have modified
1531                  * files that are in "foo/" we would lose
1532                  * them.
1533                  */
1534                 if (verify_clean_subdirectory(ce, error_type, o) < 0)
1535                         return -1;
1536                 return 0;
1537         }
1538
1539         /*
1540          * The previous round may already have decided to
1541          * delete this path, which is in a subdirectory that
1542          * is being replaced with a blob.
1543          */
1544         result = index_file_exists(&o->result, name, len, 0);
1545         if (result) {
1546                 if (result->ce_flags & CE_REMOVE)
1547                         return 0;
1548         }
1549
1550         return o->gently ? -1 :
1551                 add_rejected_path(o, error_type, name);
1552 }
1553
1554 /*
1555  * We do not want to remove or overwrite a working tree file that
1556  * is not tracked, unless it is ignored.
1557  */
1558 static int verify_absent_1(const struct cache_entry *ce,
1559                            enum unpack_trees_error_types error_type,
1560                            struct unpack_trees_options *o)
1561 {
1562         int len;
1563         struct stat st;
1564
1565         if (o->index_only || o->reset || !o->update)
1566                 return 0;
1567
1568         len = check_leading_path(ce->name, ce_namelen(ce));
1569         if (!len)
1570                 return 0;
1571         else if (len > 0) {
1572                 char *path;
1573                 int ret;
1574
1575                 path = xmemdupz(ce->name, len);
1576                 if (lstat(path, &st))
1577                         ret = error_errno("cannot stat '%s'", path);
1578                 else
1579                         ret = check_ok_to_remove(path, len, DT_UNKNOWN, NULL,
1580                                                  &st, error_type, o);
1581                 free(path);
1582                 return ret;
1583         } else if (lstat(ce->name, &st)) {
1584                 if (errno != ENOENT)
1585                         return error_errno("cannot stat '%s'", ce->name);
1586                 return 0;
1587         } else {
1588                 return check_ok_to_remove(ce->name, ce_namelen(ce),
1589                                           ce_to_dtype(ce), ce, &st,
1590                                           error_type, o);
1591         }
1592 }
1593
1594 static int verify_absent(const struct cache_entry *ce,
1595                          enum unpack_trees_error_types error_type,
1596                          struct unpack_trees_options *o)
1597 {
1598         if (!o->skip_sparse_checkout && (ce->ce_flags & CE_NEW_SKIP_WORKTREE))
1599                 return 0;
1600         return verify_absent_1(ce, error_type, o);
1601 }
1602
1603 static int verify_absent_sparse(const struct cache_entry *ce,
1604                                 enum unpack_trees_error_types error_type,
1605                                 struct unpack_trees_options *o)
1606 {
1607         enum unpack_trees_error_types orphaned_error = error_type;
1608         if (orphaned_error == ERROR_WOULD_LOSE_UNTRACKED_OVERWRITTEN)
1609                 orphaned_error = ERROR_WOULD_LOSE_ORPHANED_OVERWRITTEN;
1610
1611         return verify_absent_1(ce, orphaned_error, o);
1612 }
1613
1614 static int merged_entry(const struct cache_entry *ce,
1615                         const struct cache_entry *old,
1616                         struct unpack_trees_options *o)
1617 {
1618         int update = CE_UPDATE;
1619         struct cache_entry *merge = dup_entry(ce);
1620
1621         if (!old) {
1622                 /*
1623                  * New index entries. In sparse checkout, the following
1624                  * verify_absent() will be delayed until after
1625                  * traverse_trees() finishes in unpack_trees(), then:
1626                  *
1627                  *  - CE_NEW_SKIP_WORKTREE will be computed correctly
1628                  *  - verify_absent() be called again, this time with
1629                  *    correct CE_NEW_SKIP_WORKTREE
1630                  *
1631                  * verify_absent() call here does nothing in sparse
1632                  * checkout (i.e. o->skip_sparse_checkout == 0)
1633                  */
1634                 update |= CE_ADDED;
1635                 merge->ce_flags |= CE_NEW_SKIP_WORKTREE;
1636
1637                 if (verify_absent(merge,
1638                                   ERROR_WOULD_LOSE_UNTRACKED_OVERWRITTEN, o)) {
1639                         free(merge);
1640                         return -1;
1641                 }
1642                 invalidate_ce_path(merge, o);
1643         } else if (!(old->ce_flags & CE_CONFLICTED)) {
1644                 /*
1645                  * See if we can re-use the old CE directly?
1646                  * That way we get the uptodate stat info.
1647                  *
1648                  * This also removes the UPDATE flag on a match; otherwise
1649                  * we will end up overwriting local changes in the work tree.
1650                  */
1651                 if (same(old, merge)) {
1652                         copy_cache_entry(merge, old);
1653                         update = 0;
1654                 } else {
1655                         if (verify_uptodate(old, o)) {
1656                                 free(merge);
1657                                 return -1;
1658                         }
1659                         /* Migrate old flags over */
1660                         update |= old->ce_flags & (CE_SKIP_WORKTREE | CE_NEW_SKIP_WORKTREE);
1661                         invalidate_ce_path(old, o);
1662                 }
1663         } else {
1664                 /*
1665                  * Previously unmerged entry left as an existence
1666                  * marker by read_index_unmerged();
1667                  */
1668                 invalidate_ce_path(old, o);
1669         }
1670
1671         do_add_entry(o, merge, update, CE_STAGEMASK);
1672         return 1;
1673 }
1674
1675 static int deleted_entry(const struct cache_entry *ce,
1676                          const struct cache_entry *old,
1677                          struct unpack_trees_options *o)
1678 {
1679         /* Did it exist in the index? */
1680         if (!old) {
1681                 if (verify_absent(ce, ERROR_WOULD_LOSE_UNTRACKED_REMOVED, o))
1682                         return -1;
1683                 return 0;
1684         }
1685         if (!(old->ce_flags & CE_CONFLICTED) && verify_uptodate(old, o))
1686                 return -1;
1687         add_entry(o, ce, CE_REMOVE, 0);
1688         invalidate_ce_path(ce, o);
1689         return 1;
1690 }
1691
1692 static int keep_entry(const struct cache_entry *ce,
1693                       struct unpack_trees_options *o)
1694 {
1695         add_entry(o, ce, 0, 0);
1696         return 1;
1697 }
1698
1699 #if DBRT_DEBUG
1700 static void show_stage_entry(FILE *o,
1701                              const char *label, const struct cache_entry *ce)
1702 {
1703         if (!ce)
1704                 fprintf(o, "%s (missing)\n", label);
1705         else
1706                 fprintf(o, "%s%06o %s %d\t%s\n",
1707                         label,
1708                         ce->ce_mode,
1709                         oid_to_hex(&ce->oid),
1710                         ce_stage(ce),
1711                         ce->name);
1712 }
1713 #endif
1714
1715 int threeway_merge(const struct cache_entry * const *stages,
1716                    struct unpack_trees_options *o)
1717 {
1718         const struct cache_entry *index;
1719         const struct cache_entry *head;
1720         const struct cache_entry *remote = stages[o->head_idx + 1];
1721         int count;
1722         int head_match = 0;
1723         int remote_match = 0;
1724
1725         int df_conflict_head = 0;
1726         int df_conflict_remote = 0;
1727
1728         int any_anc_missing = 0;
1729         int no_anc_exists = 1;
1730         int i;
1731
1732         for (i = 1; i < o->head_idx; i++) {
1733                 if (!stages[i] || stages[i] == o->df_conflict_entry)
1734                         any_anc_missing = 1;
1735                 else
1736                         no_anc_exists = 0;
1737         }
1738
1739         index = stages[0];
1740         head = stages[o->head_idx];
1741
1742         if (head == o->df_conflict_entry) {
1743                 df_conflict_head = 1;
1744                 head = NULL;
1745         }
1746
1747         if (remote == o->df_conflict_entry) {
1748                 df_conflict_remote = 1;
1749                 remote = NULL;
1750         }
1751
1752         /*
1753          * First, if there's a #16 situation, note that to prevent #13
1754          * and #14.
1755          */
1756         if (!same(remote, head)) {
1757                 for (i = 1; i < o->head_idx; i++) {
1758                         if (same(stages[i], head)) {
1759                                 head_match = i;
1760                         }
1761                         if (same(stages[i], remote)) {
1762                                 remote_match = i;
1763                         }
1764                 }
1765         }
1766
1767         /*
1768          * We start with cases where the index is allowed to match
1769          * something other than the head: #14(ALT) and #2ALT, where it
1770          * is permitted to match the result instead.
1771          */
1772         /* #14, #14ALT, #2ALT */
1773         if (remote && !df_conflict_head && head_match && !remote_match) {
1774                 if (index && !same(index, remote) && !same(index, head))
1775                         return reject_merge(index, o);
1776                 return merged_entry(remote, index, o);
1777         }
1778         /*
1779          * If we have an entry in the index cache, then we want to
1780          * make sure that it matches head.
1781          */
1782         if (index && !same(index, head))
1783                 return reject_merge(index, o);
1784
1785         if (head) {
1786                 /* #5ALT, #15 */
1787                 if (same(head, remote))
1788                         return merged_entry(head, index, o);
1789                 /* #13, #3ALT */
1790                 if (!df_conflict_remote && remote_match && !head_match)
1791                         return merged_entry(head, index, o);
1792         }
1793
1794         /* #1 */
1795         if (!head && !remote && any_anc_missing)
1796                 return 0;
1797
1798         /*
1799          * Under the "aggressive" rule, we resolve mostly trivial
1800          * cases that we historically had git-merge-one-file resolve.
1801          */
1802         if (o->aggressive) {
1803                 int head_deleted = !head;
1804                 int remote_deleted = !remote;
1805                 const struct cache_entry *ce = NULL;
1806
1807                 if (index)
1808                         ce = index;
1809                 else if (head)
1810                         ce = head;
1811                 else if (remote)
1812                         ce = remote;
1813                 else {
1814                         for (i = 1; i < o->head_idx; i++) {
1815                                 if (stages[i] && stages[i] != o->df_conflict_entry) {
1816                                         ce = stages[i];
1817                                         break;
1818                                 }
1819                         }
1820                 }
1821
1822                 /*
1823                  * Deleted in both.
1824                  * Deleted in one and unchanged in the other.
1825                  */
1826                 if ((head_deleted && remote_deleted) ||
1827                     (head_deleted && remote && remote_match) ||
1828                     (remote_deleted && head && head_match)) {
1829                         if (index)
1830                                 return deleted_entry(index, index, o);
1831                         if (ce && !head_deleted) {
1832                                 if (verify_absent(ce, ERROR_WOULD_LOSE_UNTRACKED_REMOVED, o))
1833                                         return -1;
1834                         }
1835                         return 0;
1836                 }
1837                 /*
1838                  * Added in both, identically.
1839                  */
1840                 if (no_anc_exists && head && remote && same(head, remote))
1841                         return merged_entry(head, index, o);
1842
1843         }
1844
1845         /* Below are "no merge" cases, which require that the index be
1846          * up-to-date to avoid the files getting overwritten with
1847          * conflict resolution files.
1848          */
1849         if (index) {
1850                 if (verify_uptodate(index, o))
1851                         return -1;
1852         }
1853
1854         o->nontrivial_merge = 1;
1855
1856         /* #2, #3, #4, #6, #7, #9, #10, #11. */
1857         count = 0;
1858         if (!head_match || !remote_match) {
1859                 for (i = 1; i < o->head_idx; i++) {
1860                         if (stages[i] && stages[i] != o->df_conflict_entry) {
1861                                 keep_entry(stages[i], o);
1862                                 count++;
1863                                 break;
1864                         }
1865                 }
1866         }
1867 #if DBRT_DEBUG
1868         else {
1869                 fprintf(stderr, "read-tree: warning #16 detected\n");
1870                 show_stage_entry(stderr, "head   ", stages[head_match]);
1871                 show_stage_entry(stderr, "remote ", stages[remote_match]);
1872         }
1873 #endif
1874         if (head) { count += keep_entry(head, o); }
1875         if (remote) { count += keep_entry(remote, o); }
1876         return count;
1877 }
1878
1879 /*
1880  * Two-way merge.
1881  *
1882  * The rule is to "carry forward" what is in the index without losing
1883  * information across a "fast-forward", favoring a successful merge
1884  * over a merge failure when it makes sense.  For details of the
1885  * "carry forward" rule, please see <Documentation/git-read-tree.txt>.
1886  *
1887  */
1888 int twoway_merge(const struct cache_entry * const *src,
1889                  struct unpack_trees_options *o)
1890 {
1891         const struct cache_entry *current = src[0];
1892         const struct cache_entry *oldtree = src[1];
1893         const struct cache_entry *newtree = src[2];
1894
1895         if (o->merge_size != 2)
1896                 return error("Cannot do a twoway merge of %d trees",
1897                              o->merge_size);
1898
1899         if (oldtree == o->df_conflict_entry)
1900                 oldtree = NULL;
1901         if (newtree == o->df_conflict_entry)
1902                 newtree = NULL;
1903
1904         if (current) {
1905                 if (current->ce_flags & CE_CONFLICTED) {
1906                         if (same(oldtree, newtree) || o->reset) {
1907                                 if (!newtree)
1908                                         return deleted_entry(current, current, o);
1909                                 else
1910                                         return merged_entry(newtree, current, o);
1911                         }
1912                         return reject_merge(current, o);
1913                 } else if ((!oldtree && !newtree) || /* 4 and 5 */
1914                          (!oldtree && newtree &&
1915                           same(current, newtree)) || /* 6 and 7 */
1916                          (oldtree && newtree &&
1917                           same(oldtree, newtree)) || /* 14 and 15 */
1918                          (oldtree && newtree &&
1919                           !same(oldtree, newtree) && /* 18 and 19 */
1920                           same(current, newtree))) {
1921                         return keep_entry(current, o);
1922                 } else if (oldtree && !newtree && same(current, oldtree)) {
1923                         /* 10 or 11 */
1924                         return deleted_entry(oldtree, current, o);
1925                 } else if (oldtree && newtree &&
1926                          same(current, oldtree) && !same(current, newtree)) {
1927                         /* 20 or 21 */
1928                         return merged_entry(newtree, current, o);
1929                 } else
1930                         return reject_merge(current, o);
1931         }
1932         else if (newtree) {
1933                 if (oldtree && !o->initial_checkout) {
1934                         /*
1935                          * deletion of the path was staged;
1936                          */
1937                         if (same(oldtree, newtree))
1938                                 return 1;
1939                         return reject_merge(oldtree, o);
1940                 }
1941                 return merged_entry(newtree, current, o);
1942         }
1943         return deleted_entry(oldtree, current, o);
1944 }
1945
1946 /*
1947  * Bind merge.
1948  *
1949  * Keep the index entries at stage0, collapse stage1 but make sure
1950  * stage0 does not have anything there.
1951  */
1952 int bind_merge(const struct cache_entry * const *src,
1953                struct unpack_trees_options *o)
1954 {
1955         const struct cache_entry *old = src[0];
1956         const struct cache_entry *a = src[1];
1957
1958         if (o->merge_size != 1)
1959                 return error("Cannot do a bind merge of %d trees",
1960                              o->merge_size);
1961         if (a && old)
1962                 return o->gently ? -1 :
1963                         error(ERRORMSG(o, ERROR_BIND_OVERLAP),
1964                               super_prefixed(a->name),
1965                               super_prefixed(old->name));
1966         if (!a)
1967                 return keep_entry(old, o);
1968         else
1969                 return merged_entry(a, NULL, o);
1970 }
1971
1972 /*
1973  * One-way merge.
1974  *
1975  * The rule is:
1976  * - take the stat information from stage0, take the data from stage1
1977  */
1978 int oneway_merge(const struct cache_entry * const *src,
1979                  struct unpack_trees_options *o)
1980 {
1981         const struct cache_entry *old = src[0];
1982         const struct cache_entry *a = src[1];
1983
1984         if (o->merge_size != 1)
1985                 return error("Cannot do a oneway merge of %d trees",
1986                              o->merge_size);
1987
1988         if (!a || a == o->df_conflict_entry)
1989                 return deleted_entry(old, old, o);
1990
1991         if (old && same(old, a)) {
1992                 int update = 0;
1993                 if (o->reset && o->update && !ce_uptodate(old) && !ce_skip_worktree(old)) {
1994                         struct stat st;
1995                         if (lstat(old->name, &st) ||
1996                             ie_match_stat(o->src_index, old, &st, CE_MATCH_IGNORE_VALID|CE_MATCH_IGNORE_SKIP_WORKTREE))
1997                                 update |= CE_UPDATE;
1998                 }
1999                 add_entry(o, old, update, 0);
2000                 return 0;
2001         }
2002         return merged_entry(a, old, o);
2003 }